Hypertensive emergencies
Requirement to reduce blood pressure over hours (hi BP is causing end organ damage) rather than weeks. Remember that illicit drugs particularly cocaine may cause acute hypertension.
Signs end organ damage
- Encephalopathy (or stroke)
- Intra-cranial Haemorrhage
- Myocardial ischaemia/AMI
- Aortic dissection
- Acute heart failure
- Eclampsia
- Acute renal failure
Examine for:
- Lying & standing BP (volume status)
- BP both arms (aortic dissection)
- Heart failure
- Fundoscopy (haemorrhages, papilloedema, exudates)
- Neurological exam (lateralising signs / meningism)
Investigations
- ECG (ischaemia)
- Dipstick urine
- CXR (dissection or APO)
- U&E & Creat
- ßHCG (eclampsia)
- +/- CT Chest
- +/- CT Brain
If end organ damage, goal is to reduce MAP by 25% in st hour then 25% over next 24 hours
MAP = [(Dia BP x2) + Sys BP] / 3
Treatment suggestions for hypertension with end organ damage
Acute renal failure / insufficiency
- Ca++ antagonists. Beware heart failure (clinical overload). Beware HYPOvolaemia.
Aortic dissection (aim for max Sys BP 110)
- Β-blockers (Labetalol) first line +/- nitrates
Herat failure or ischaemia
- GTN (SL and then IV), ACEI, diuretic if not hypovolaemic,Β-blockers
Eclampsia
- Β-blockers (or Hydralazine), sedation
Stroke or SAH
- Labetalol - please see management of hypertension in Stroke
Encephalopathy
- Nirtoprusside or labetalol
| Agent | Dose | Indications |
|---|---|---|
Sodium Nitroprusside |
Initially 0.5-1.5µg/kg/min Titrate up in increments of 0.5µg/kg/min Max up to 8µg/kg/min |
Hypertensive encephalopathy Myocardial ischaemia Pulmonary oedema Aortic dissection (+ ß blocker) |
Labetalol |
Initial 20-50mg slow bolus Then infusion 2mg/min, titrated as required |
Stroke syndromes Hypertensive encephalopathy Aortic dissection Phaeochromocytoma Eclampsia |
Nitrates |
Isosorbide Dinitrate 2-10mg/hr max 20mg/hr Glyceryl Trinitrate 10-20µg/min max 200µg/min |
Cardiac ischaemia Pulmonary oedema |
Initiation of treatment for patients WITHOUT end organ damage
Only in exceptional circumatance should antihypertensive treat ement be intitated in the emergency department (signs of end organ damage)- GP should confirm (> 140/90 mmHg) on at least two visits.
- Routine ambulatory blood pressure monitoring is of unproven value.
- Please ask GP to formally assess cardiovascular risk +/- refer to OPD.
- Formally assess their cardiovascular risk.
- Accelerated (malignant) hypertension and suspected phaeochromocytoma require immediate referral.
- GP may start medications in patients with :
- Persistent BP > 160/100
- Raised cardiovascular risk and BP > 140/90
- In hypertensive patients aged > 55 or older or black patients of any age, the first choice drug should be
- Either a calcium-channel blocker or a thiazide-type diuretic
- In hypertensive patients younger < 55, the first choice for initial therapy should be
- An angiotensin-converting enzyme (ACE) inhibitor (or an angiotensin-II receptor antagonist if an ACE inhibitor is not tolerated).
